1. Field of the Invention
The present invention relates generally to furnace tube inspection systems, and more particularly to a system and method for displaying inspection data in a two-dimensional and/or three-dimensional format to enable visual detection of problem areas within the furnace.
2. Description of Related Art
As depicted in FIGS. 1A-1C, a furnace is generally comprised of several hundred to several thousand feet of serpentine tubing that is characterized by straight tube segments (each of which is identified as reference numeral 10) interconnected by angled bends (each of which is identified as reference numeral 20). The bends allow tight stacking of the tube segments for maximum heat transfer and efficiency. Although not shown in FIGS. 1A-1C, medium length sections of tubing may also be used to interconnect furnace tubing located in different regions of the furnace. These sections of tubing are not part of the furnace geometry, but are employed so that an inspection tool (described below) can be operated in one pass, if possible, and thus significantly reduce plant downtime.
If the plant maintenance personnel need to repair or replace a worn section of the furnace, it is very important to accurately identify which tube segment contains the worn section and where the identified tube segment is located within the furnace. In addition, it is important to obtain information regarding hot spots in the furnace so that the plant maintenance personnel may adjust the furnace to reduce or eliminate the hot spots and thereby prolong the life of the furnace and reduce cost and future plant downtime.
In this regard, furnace tube inspection systems have been developed in which an inspection tool (identified as reference numeral 30) is flushed from a launcher (shown in FIG. 1A) through the furnace (shown in FIG. 1B) and to a receiver (shown in FIG. 1C). Typically, the inspection tool collects inspection data at pre-determined time intervals as it progresses through the furnace (although the inspection data may alternatively be collected via a position-based collection system). The inspection data includes readings of the inside radius of the furnace, readings of the wall thickness of the furnace, and the like. The collected inspection data is then extracted from the inspection tool, whereby the various readings are converted to calibrated engineering units. Finally, the converted inspection data may be examined by an engineer in order to identify thinning, bulging and other flaws within the furnace.
One problem with the furnace tube inspection systems of the prior art is that it is difficult to correlate the inspection data collected from the furnace with the physical geometry of the furnace. This is due to the fact that the inspection tool does not progress through the furnace at a constant rate. Instead, the inspection tool will often ebb and flow through the furnace and/or may become momentarily stuck at a point in the structure. Also, the inspection tool may take longer to traverse a bend in the furnace. In addition, the furnace may change in schedule size or diameter and thus retard or promote the passing of the inspection tool. For example, the furnace could change from a schedule 40 to a schedule 80 (or vice versa) and thus change the rate of passage of the inspection tool, or, the furnace could change from a 4-inch inside diameter to a 6-inch inside diameter (or vice versa) and thus change the rate of passage of the inspection tool. All of these conditions generate a correlation (i.e., mapping or scaling) problem between the collected inspection data and the precise location of the inspection tool with respect to the physical geometry of the furnace. As a result, an engineer may not be able to identify the precise locations of the worn sections and/or hot spots of the furnace.
Another problem with the furnace tube inspection systems of the prior art is that the inspection data is not displayed in a manner that readily “announces” problem areas within the furnace. Conventionally, the inspection data has been presented in a one-dimensional tabular format, which is deficient in that an engineer must peruse each line of data to determine if a potential problem has arisen. It can be appreciated that this method of examining the inspection data is time-consuming, inefficient, and does not readily permit a comparison between one section of tubing and another. As such, the engineer is not able to readily detect worn sections of the furnace, and, cannot determine if hot spots are occurring during the operation of the furnace that are common to a region of the furnace.
Recently, data visualization tools have been developed that allow a slice of the inspection data to be graphically displayed in a two-dimensional format, wherein each slice comprises inspection data collected from a short axial section (e.g., less than a foot) of the furnace. While this graphical representation of the inspection data is an improvement over the one-dimensional tabular format described above, the engineer may only view one slice of the inspection data at a time. This is a significant problem when attempting to identify overall trends in the inspection data and then apply them to the real world operation of the plant.